Notes for lcm and gcd, formatting doc fixes (#41526)
Summary:
A small PR fixing some formatting in lcm, gcd, and the serialization note. Adds a note to lcm and gcd explaining behavior that is not always defined.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/41526
Reviewed By: ngimel
Differential Revision: D22569341
Pulled By: mruberry
fbshipit-source-id: 5f5ff98c0831f65e82b991ef444a5cee8e3c8b5a
